Minimally invasive techniques for providing medical examinations and therapies frequently employ endoscopes, such as a bronchoscope, ureteroscope, or flexible sigmoidoscope. Endoscopes such as these typically employ fiber optic or CCD imaging devices to enable the practitioner to visually inspect otherwise inaccessible areas of the anatomy such as the lungs, the ureter and kidneys, the colon, etc. These endoscopes also typically contain a tube, called the working channel, through which solutions such as anesthetics can be administered and bodily materials such as mucus can be withdrawn, typically via suction. In addition to use in administering and removing liquids or other material, the working channel of an endoscope is used to pass slender instruments to perform other functions at the distal end of the scope, under visual guidance through the endoscope.
Instruments typically used in this manner include forceps for grasping objects or for pinching and removing small tissue samples, biopsy needles for removing deep tissue samples in the lumen of a needle, snares or baskets for capturing and withdrawing objects such as an aspirated peanut from the lungs or a kidney stone from the calyxes of the kidney, and a wide variety of other tools.
Manipulation of these tools requires simultaneous manipulation or stabilization of the endoscope, along with manipulation of the working channel tool itself. The endoscope can typically be maneuvered along three, four or more degrees of freedom, including insertion and withdrawal, rotation, and tip flexion in one or two dimensions (up/down and/or left/right). The working channel tool is maneuvered along an additional two or more degrees of freedom, including insertion/withdrawal, rotation, and tool actuation, etc. Tool actuation can include, for example, opening and closing the jaws of a biopsy forceps, controlling the plunge of a biopsy needle, actuating a cauterization or ablation tool, pulsing a laser, or opening and closing a snare or basket. The tasks of manipulating and stabilizing the three or more degrees of freedom of the endoscope, while simultaneously manipulating the multiple degrees of freedom of the working channel tool are difficult to perform, and frequently the practitioner uses an assistant to manipulate one or more of the degrees of freedom, such as working channel tool actuation.
The present invention relates to a device or system that extends the functionality of the working channel of an endoscope by adding devices for sensing motion of the working channel tool and for application of motive force to assist the practitioner in manipulation of the instrument in the working channel.
In one mode of use, the system uses drive wheels driven by a motor or other device to permit the practitioner to quickly exchange working channel tools, by smoothly moving the current tool out of the working channel, and then quickly moving in the new tool to a point just short of exiting the working channel. At this point the practitioner takes over and performs the fine motor skills necessary to move the tool out of the endoscope and into a position to interact with the anatomy. In another mode of operation the physician manipulates tools manually and is provided with tactile guidance via a set of driven or braked drive wheels. One form of guidance is the provision of notification that the tool is approaching the end of the endoscope and is about to emerge from the endoscope. A braking or other tactile force would signal nearing the end of the working channel, enabling the user to move the tool quickly within the working channel without danger of moving the tool too rapidly out of the working channel, thereby reducing the risk of damage or injury to tissue adjacent the distal end of the endoscope.
In another embodiment, the sensor and drive assembly is coupled to a catheter through which instruments and tools are passed into the vascular system. For instance, in the process of implantation of a heart pacing lead, the cardiologist must make a number of fine adjustments in the position of a guide catheter, then attempt to stabilize it while inserting an additional element through the lumen of the stabilized catheter. In one mode, the sensor/drive assembly is commanded to maintain a position using passive or active braking force. In another mode, the tip of the catheter is instrumented and an active mechanism commands insertion/retraction and roll increments to stabilize the actual position of the distal end.
In yet another embodiment, the sensor and drive assembly is instrumented with strain gauges or other devices to detect forces encountered at the distal end of the catheter or working channel tool. These forces are then amplified and displayed to the user via a motor or other motive mechanism.
In another embodiment, the sensor and drive assembly detect and modify motions, for example detecting and filtering out high frequency jitter caused by the user. This superstabilization mode is useful in situations where fine motor control is required.
In another embodiment, signals from a device inserted in the working channel are used to command the motive device to maintain a particular quality of electrical contact with the anatomy. In this situation, electrical impedance is changed by the force of contact. A desired quality of contact is initially attained by the physician, then the device is commanded to control contact force automatically to maintain the particular quality of contact.
The above and still further features and advantages of the present invention will become apparent upon consideration of the following detailed description of specific embodiments thereof, particularly when taken in conjunction with the accompanying drawings wherein like reference numerals in the various figures are utilized to designate like components.